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Recombination of ions in plasma at 50-300 K
Rubovič, Peter ; Glosík, Juraj (advisor) ; Fárník, Michal (referee) ; Korolov, Ihor (referee)
A B S T R A C T Title: Recombination of Ions in Plasma at 50 − 300 K Author: Peter Rubovič Supervisor: Prof. RNDr. Juraj Glosík, DrSc. Abstract: Main part of this doctoral thesis lies in a study of recom- bination of atomic and molecular ions in low temperature plasmatic environment with emphasis on effect of third bodies. Stationary After- glow equipped with Cavity Ring Down Spectrometer and Cryogenic Flowing Afterglow with Langmuir Probe II were used to obtain recom- bination rate coefficients. Electron assisted collisional radiative recom- bination of Ar+ ion was studied in the temperature range of 50−100 K and helium assisted collisional radiative recombination was observed too. Both H+ 3 and its isotopologue D+ 3 were studies in flowing after- glow and spectroscopically in stationary afterglow as well. Binary re- combination rate coefficients and ternary recombination rate coeffi- cients for helium assisted ternary recombination were determined in the temperature range of 50 − 250 K. These coefficients were deter- mined also for pure ortho- and para- nuclear spin configurations of H+ 3 in the temperature range of 80 − 200 K. Keywords: dissociative recombination, collisional radiative recombi- nation, H+ 3 , D+ 3 , Ar+ viii
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Negative Ion Astrochemistry - a Laboratory Study
Jusko, Pavol ; Glosík, Juraj (advisor) ; Fárník, Michal (referee) ; Korolov, Ihor (referee)
A B S T R A C T Presented work focuses on experimental study of anion interaction with neutral particles at temperatures relevant for astrophysics. Anion H− , important for molecular hydrogen creation, and O− as a possible source of water are investigated. The temperature dependence of reac- tion rate coefficients from 10 to 150 K for reactions H− + H → H2 + e− and O− + H2 → H2O + e− has been determined. The energy distri- bution of electrons produced in the latter reaction at 300 K has also been acquired. These studies have been performed on two experimen- tal setups, which are presented together with the theory of operation, construction details, calibration, and supporting test measurements.
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Implementation of ion imaging technique in experiments with free molecules, clusters and nanoparticles
Kočišek, Jaroslav ; Fárník, Michal (advisor) ; Klán, Petr (referee) ; Glosík, Juraj (referee)
Title: Implementation of ion imaging technique in experiments with free molecules, clusters and nanoparticles Author: Jaroslav Kočišek Department: Department of Surface and Plasma Science Supervisor: Mgr. Michal Fárník, PhD., DSc., Ústav fyzikální chemie J. Hey- rovského, AV ČR, v.v.i. Abstract: The experimental work is focused on implementation of novel tech- niques to study clusters and nanoparticles in molecular beams. A new exper- imental system was tested, which combines the technique of velocity map ion imaging with pulsed molecular beam source. The same method and new mass spectrometer were implemented on the apparatus with molecular beam of size selected clusters. The new methods were used to study environmental effects on photo and electron induced chemistry. The most important results concerns on influence of expansion conditions on the structure of formed neutral clusters of HBr and C2H2. Results of experiments with HNO3 and CF2Cl2 molecules are then crucial for understanding heterogeneous processes in the Stratosphere. Keywords: ion imaging, mass spectrometry, molecular beams, photochemistry, nanoparticles
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Solvent Influence on Photochemistry of Small Biomolecules in Clusters
Profant, V. ; Dian, J. ; Fárník, Michal ; Poterya, Viktoriya
We present a photolysis study of pyrrole, imidazole and pyrazole clusters in comparison to the photolysis of the isolated molecules. Size distributions of different mean cluster sizes have been prepared and characterized in supersonic expansions. The clusters were photolyzed at 243 and 193 nm and the kinetic energy distributions (KEDs) of the H-fragments were measured. The KEDs of all systems exhibit a bimodal character with slow and fast H-fragment peaks similar to the spectra of the corresponding single molecules. However, with the increasing clusters size the slow component gains on intensity in comparison to the fast component. A similar effect is observed with increasing the excitation energy from 243 to 193 nm.
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Fotochemie v klastrech a nanočásticích: systémy relevantní v atmosférické chemii a v biologii
Fárník, Michal
Influence of solvation on photodissociation of molecules is investigated in clusters produced in a molecular beam experiment. Photochemistry in three different systems is compared: (i) HBrArn and (HBr)n clusters, where the fragment does not react with the solvent and an effect of the fragment caging is observed, (ii) HBr(H2O)n system where chemical reaction occurs and a reaction channel is closed by the electronic interaction with the solvent. The practical relevance of the studied processes ranges from atmospheric chemistry to biology.
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